Thermostatically controlled ignition system with retractable ignition device

ABSTRACT

A temperature sensor detects the presence of a flame by measuring the temperature near the flame site, and an actuator positions an ignition device in based on the temperature sensor&#39;s reading. The ignition device is positioned near the flame site if the flame is not present and further from the flame site if the flame is present.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram depicting one preferred embodiment of the invention.

FIG. 2 is a functional diagram depicting the pneumatic system of a preferred embodiment of the invention.

FIG. 3 is a functional diagram depicting the electrical system of a preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following are descriptions of exemplary embodiments of the invention intended to enable a person skilled in the prior art to make and use the invention. Other embodiments of the present invention are also possible and would be understood by such a person based on this specification. Nothing in these descriptions should be interpreted as limiting the scope of the invention, as there are a wide variety of materials, parts, and methods in the art that are understood to be interchangeable with those listed herein.

FIG. 1 is a diagram showing one preferred embodiment of the invention. In this exemplary embodiment, combustible material such as gas or flammable liquid is supplied via tube 102 (from a supply source 110) to maintain flame 104. At the end of tube 102 may be a flame section 103 (shown here in cross section), which is of sufficient size to allow for thermocouple 302, actuator arm 202 and ignition device 201. Supply source 110 may be a permanent fixture, or a removable source attached by suitable means, such as a hammer union.

Thermocouple 302 is positioned within flame section 103 such that it can detect the presence of flame 104 using temperature readings. Thermocouple 302 may be of any suitable type, depending on the type of flame used in the device and the particular application. The readings of thermocouple 302 are compared to certain thresholds to determine whether flame 104 is present or absent. The presence of flame 104 will cause thermocouple 302 to register a higher temperature than the absence of flame 104. One threshold may be used to indicate the presence of flame 104 (such as “any temperature over 150 degrees Fahrenheit”) and another threshold may be used to indicate the absence of flame 104 (such as “any temperature below 150 degrees Fahrenheit”). In practice, these thresholds may be set to identical temperatures, or they may be different. The thresholds will vary based on factors such as placement of thermocouple 302, temperature of flame 104, distance between thermocouple 302 and flame 104, etc. Thus, the thresholds may be adjusted based on the particular constraints of an embodiment.

Ignition device 201, which may be a pilot light, electric spark generator, or other means to ignite combustible material, is also situated within flame section 103 and is attached to one end of actuator arm 202. When positioned near the location of flame 104, ignition device 201 may be used to relight flame 104 using the combustible material from tube 102. As described below, actuator arm 202 may move along its axis as controlled by air cylinder 203 such that ignition device 201 may be positioned within flame section 103 or not. When actuator arm 202 is extended to a certain length or position, the ignition device 201 is positioned close enough to the flame 104 site to ignite flame 104 from the fuel in tube 102. When actuator arm 202 is retracted to a different length or position, the ignition device 201 is positioned further from the flame 104 location or out of the flame section 103 altogether.

The exemplary embodiment also includes control panel 105, which may include controls as needed within a given application. For example, a given embodiment may require a power switch to regulate operation, one or more dials to set the threshold temperatures as described above, or one or more dials to set the pressure thresholds for the air cylinder 203 and its associated pneumatic system as described below with reference to FIG. 2.

Control panel 105, tube 102, and air cylinder 203 may each be mounted on or to base 101, which may be of sufficient mass or size to provide stability to the system or otherwise allows the entire system to be secured in place.

In this description of a preferred embodiment, air cylinder 203 is used as an actuator for moving actuator arm 202 (and ignition device 201) into different positions. Other embodiments may instead use a linear actuator, a hydraulic actuator, or any other component that is capable of positioning the ignition device 201 in two different positions. FIG. 2, described below, depicts a mechanical system for use with a pneumatic actuator. If a different actuator were used, a corresponding mechanical system would be used. For example, a linear actuator might simply use a power source and an integrated circuit that receives a signal from the temperature controller 301, applying a corresponding voltage to the linear actuator to extend or retract.

In this exemplary embodiment, the invention may comprise a mechanical system depicted in FIG. 2, which includes a number of physical parts such as the pilot light 201, air cylinder 203, and pressure switch 212. The exemplary embodiment may also comprise an electrical system (depicted in FIG. 3) that controls the mechanical system, including a temperature controller 301 and solenoid 303. Solenoid 303 is an internal solenoid that controls the solenoid valve 206. By activating and deactivating solenoid 303, the system opens or closes solenoid valve 206, in turn activating or deactivating the actuator 201.

In this embodiment, the mechanical system comprises an actuator, such as an air cylinder 203, which is connected to an actuator arm 202. As pressure in the air cylinder 203 increases or decreases, the actuator arm 202 is moved accordingly. At the end of the actuator arm 202 is an ignition device 201, such as a pilot light, electrical sparking device, or any other means to create an ignition.

The air cylinder is 203 is connected air lines 204 and 205, which are in turn controlled by solenoid 206. If solenoid 206 is activated, air may flow into air cylinder 203, causing the actuator 202 to extend. If solenoid 206 is not activated, air may flow out of air cylinder 203 causing the actuator 202 to retract.

The system contains pressurized air in air tank 213. Air gauge 214 is configured to measure the internal pressure of the system. In the exemplary embodiment, it is desirable to maintain a certain pressure (for example, 50 psi) in order to supply air cylinder 203 with sufficient pressure. Air may flow from air tank 213, along air lines 208 and 207 (via connector 210) to supply air cylinder 203 when the solenoid 206 is activated. The desired internal pressure may vary based on the environmental conditions, air lines, air tank, actuator, etc.

If the pressure falls below a certain threshold in this embodiment (measured using air gauge 214), pressure switch 212 is activated. As described below with respect to the electrical system, this allows air pump 211 to activate and supply additional air pressure to the system through air line 209. This ensures that the internal air pressure of air tank 213 will remain sufficient to power air cylinder 203 even over several cycles of operation.

A person of ordinary skill in the art would understand that there is a great variety of parts that could be suitable for use in this invention, and that the use of any particular part may be determined by the specific application. For example, the air lines may be of any type that is appropriate for the amount of pressure needed and the various components, and the connector may be of any type that is suitable for connecting the air lines used.

FIG. 3 depicts an electrical system that may be used in a preferred embodiment of the invention to control the mechanical system depicted in FIG. 2 by activating or deactivating solenoid 303 or air pump 211 as described herein.

The electrical system 300 may include a temperature sensor, such as thermocouple 302, located proximate to the flame 104, that generates an electrical signal based on the temperature measured. In the exemplary embodiment of FIG. 3, thermocouple 302 may generate a digital or analog signal to temperature controller 301.

Temperature controller 301 is connected to the solenoid coil 303 (within solenoid valve 206) via contact 301 b. In response to a signal from thermocouple 302 that indicates a lower than desired temperature (usually indicative that flame 4 is extinguished), temperature controller 301 may activate solenoid coil 303 (inside solenoid valve 206). As described above with reference to the mechanical system, this causes actuator arm 202 to extend to relight flame 104 via ignition device 201.

Temperature controller 301 is also connected to air pump 211 via pressure switch 212. If the pressure switch is closed (indicating that the pressure is lower than desired), temperature controller 301 may activate air pump 211, which will increase the pressure accordingly. When the pressure reaches the desired threshold, for example 50 psi, the pressure switch opens. If the pressure switch is open, the air pump 211 will not be activated.

Any of the components that require a power source may be connected to battery 305, for example a 12V battery or any of the many types known in the art. In other embodiments, there may be multiple power sources of varying voltages to supply the needs of different components, or voltage regulators may be used to maintain a different voltage than battery 305. A fuse 310 may be included, or a power switch 307, to regulate electrical operation of the system. 

I claim:
 1. A system comprising: a fuel supply source; a temperature sensor; an actuator; an ignition device coupled to the actuator; a control system configured to control the actuator in response to at least a signal from the temperature sensor.
 2. The system of claim 1, wherein the actuator is a pneumatic air cylinder.
 3. The system of claim 1, wherein the actuator is a linear actuator.
 4. The system of claim 1, wherein the control system is configured to cause the actuator to position the ignition device proximate to the fuel supply source in response to a low temperature signal from the temperature sensor.
 5. The system of claim 1, wherein the control system is configured to cause the actuator to position the ignition device further away from the fuel supply source in response to a high temperature signal from the temperature sensor.
 6. The system of claim 1, wherein the fuel supply source is a supply of propane.
 7. A method for igniting a flame comprising: monitoring the temperature at a first location, said first location located proximate to a flame ignition site; comparing a temperature measurement to a first threshold and a second threshold; if the temperature measurement is below the first threshold, moving an ignition device into a first position, said first position being located close enough to a flame ignition site for the ignition device to cause ignition; and if the temperature measurement is above a second threshold, moving the ignition device to a second position, said second position not being located close enough to a flame ignition site for the ignition device to cause ignition.
 8. The method of claim 7, wherein the step of moving an ignition device into a first position comprises: activating a solenoid valve attached to an actuator attached to an actuator arm, and extending said actuator arm, said actuator arm having the ignition device attached.
 9. The method of claim 7, wherein the step of moving the ignition device to a second position comprises: deactivating a solenoid valve attached to an actuator arm, and retracting said actuator arm, said actuator arm having the ignition device attached.
 10. The method of claim 7, wherein the actuator is an air cylinder actuator and the step of activating a solenoid valve attached to an actuator arm comprises increasing the air pressure within the air cylinder actuator.
 11. A system comprising: a fuel supply source; a tube coupled to the fuel supply source, said tube having an opening at one end to allow the passage of fuel out of the tube; a temperature sensor located proximate to the opening of the tube; an actuator arm coupled at one end to an actuator and having at the opposite end an ignition device; wherein the actuator may selectively extend or retract the actuator arm; wherein said extension causes the ignition device to be positioned relative to the opening of the tube at a first position; wherein said retracting cause the ignition device to be positioned relative to the opening of the tube at a second position; wherein said first position is proximate to the opening of the tube such that the ignition device may ignite fuel passing through the opening; wherein said second position is removed from the opening of the tube such that the ignition device may not ignite fuel passing through the opening; a control system coupled to the temperature sensor and the actuator; wherein the control system receives a temperature signal from the temperature sensor relating to the temperature measured by said sensor; wherein the actuator extends or retracts the actuator arm in response to a signal from the control system; wherein said control system is configured to cause the actuator to extend the actuator arm in response to a temperature signal below a first threshold; and wherein said control system is configured to cause the actuator to retract the actuator arm in response to a temperature signal above a second threshold;
 12. The system of claim 11, wherein the actuator is a pneumatic actuator, the system further comprising: an air container for storing pressurized air; a pressure gauge coupled to the air container and capable of measuring the air pressure within the air container; an air pump coupled to the air container and capable of increasing the pressure of the air within the air container; and a valve coupled to the air container and further coupled to the pneumatic actuator, selectively allowing air to travel from the air container to the pneumatic actuator or the reverse.
 13. The system of claim 12, wherein the valve is a solenoid valve; wherein the solenoid valve comprises a control solenoid that is connected to the control system; and wherein the solenoid valve is configured to selectively open and close responsive to signals from the control system.
 14. The system of claim 11, wherein the actuator is a linear actuator.
 15. The system of claim 11, wherein the first position is such that the ignition device is within 6 inches of the opening.
 16. The system of claim 11, wherein the second position is such that the ignition device is more than 12 inches from the opening.
 17. The system of claim 11, wherein the first threshold is less than 120 degrees Fahrenheit.
 18. The system of claim 11, wherein the second threshold is at least 200 degrees Fahrenheit.
 19. The system of claim 11, wherein the fuel supply source is a supply of propane. 